The present invention relates to clean air systems and in particular, but not exclusively, to clean air systems for use in operating theatres, pharmaceutical product manufacture, semiconductor manufacture and the like.
In known clean air systems air is passed through a filter and directed towards an area to be kept free from contamination (a "clean area").
In known clean air systems it is necessary to ensure that contaminated air does not become mixed with the filtered air in the clean area. This can be achieved by, for example, discharging the filtered air with a differential velocity profile. In our "EXFLOW" system this is achieved by discharging filtered air with a higher velocity at the centre than at the periphery in order to form a generally outward flow of air out of the clean area, making it more difficult for contaminated air to enter the clean area.